[FEATURE] Middelware extension/Build steps for serving

[sebbi08]

Expected Behavior

Have the posibility to modify served files like transpiling from es6 to es5 without the need of writing an own server.

Current Behavior

The server only combies the project with its dependencies and only for certain files (theme css,version.json,discovery page) generates the on the fly.

Context

• UI5 Module Version (output of ui5 --version when using the CLI): all
• Node.js Version: all
• npm Version: all
• OS/Platform: all
• Other information: all

Affected components (if known)

• ui5-builder
• ui5-server
• ui5-cli
• ui5-fs
• ui5-project
• ui5-logger

Proposal

This also might be possible in multiple ways.
The first way would be to make the middelwares the server uses extentable. This would allow to add tasks like transpiling,preloading. For preloading this might not be the best way to do this becuase in big projects/libraries this might take some time to generate the preload.

The second way would be to run some build tasks when serving and then afterwards on file change. This would make the initial call longer but reduce the serving time. Also it would make the combination of several tasks on one file easier because when serving the preload you might also transpile the js code boefore generating the preload.

[cschuff]

Providing an easy (and well documented) way to hook in custom middleware will give the developer full flexibility to adapt the server however one wants and save you guys from having to implement tons of functionality that does not necessarily belong in the tooling.

I'd strongly prefer extensible tooling with a cookbook/example repo over a bloated, unusable and probably still not sufficient ui5-tooling...

BR
Chris

[RandomByte]

Thank you for this issue. It sounds very similar to what we plan to do with the "middleware extensibility" bullet point in our roadmap.

We would first start with writing an RFC on it. But the topic should be pretty straight forward.

We would also want to offer the other way around: Consuming UI5 Server middleware in your own server implementation. Technically this is already possible, but the middleware functions are not yet public API. Mainly because we are not yet sure about their signatures. This is likely to clear up in the process of defining the signature for extension middleware.

[RandomByte]

RFC started: #151

[sebbi08]

Hi we tested the and found it working thank you all